With the advent of cloud computing and data center based services, requests for high bandwidth and dynamic end-to-end (E2E) connectivity are enormously increased. Networks may be composed of heterogeneous domains that differ in, for example, management and geographic locations, and may have vendor-specific technologies. In this context, to efficiently manage the network and automatically provide E2E connection becomes critical. The sharing of local information, such as the complete network topology, becomes difficult, especially if network domains are managed by different entities. An efficient abstraction of the transport layer simplifies interworking of different administrative and technology domains and enables E2E routing solutions.
Network virtualization is a promising trend of enabling effective management of networks. In this context the transport network assumes a new role of providing dynamically E2E connectivity. One of the main aspects of network virtualization is the ability to create a smart logical and abstract view of the physical network resources (like packet and optical switches, routers, etc.) that allows for hiding hardware complexity and constraints.
Data centers may be distributed around a network, either in parts of the network with high throughput, or near the access part of the network. Data centers may provide some services, for example user interactive services such as web gaming, that require guarantees of low network delays, and may also provide some other services, for example particularly data-intensive services, that require guarantees of a particular data throughput.
Physical resources still need to be allocated in such a virtualized network.